The present invention relates to a magnetic field enhanced sputtering arrangement having a drive housing which forms the arrangement housing, and a rotor which is connected to a magnet carrier arrangement in a torsion-tight or non-rotatable manner. The present invention also relates to a vacuum treatment apparatus equipped with the magnetic field enhanced sputtering arrangement of the invention.
It is known to sputter materials, be they electrically conducting or electrically insulating, in vacuo, wherein an electric field is generated in a reaction chamber, between the surface of the material to be sputtered, i.e., the target surface and a counter electrode. A plasma discharge is formed, and with the positive ions of a gas introduced into the reaction chamber, the surface of the material to be sputtered is sputtered. The material thus sputtered is used either directly for coating workpieces in the chamber, or in the form of a reaction product after reacting with a reactive gas supplied to the chamber.
Such sputtering processes are carried out in DC plasmas, HF plasmas, or in plasmas which are generated by DC and superimposed AC.
In spite of entirely different details in the mechanism of a sputtering process proper, for the stated case of plasma excitation, it is further known to increase the plasma density and therewith the sputtering rate by generating a magnetic field in the region of the target surface to be sputtered. A sputtering process of this type, which is enhanced by a magnetic field, is known for example by the term magnetron sputtering.
It is further known to close at least partially, the flux of this magnetic field, by forming a tunnel thereof over the target surface.
Moreover, it is known, such as for example for magnetron sputtering, from EP-0 399 710, U.S. Pat. No. 5,130,005, DE-A-33 31 245 or as depicted in DE-A-35 06 227, to move the flux of the magnetic field with respect to the target surface, and in this way to reach the range of the maximum sputtering rate, be this in order to sputter the target as uniformly as possible, or in order to achieve, on the work piece, a desired distribution of the rate of deposition of the material.
It is also known in reactive sputtering to move the flux relative to the sputtered surface.
Additionally, the provided target arrangements can be planar in this arrangement, as is the case with the known planar magnetron arrangement, or they can define volume surfaces, such as for example concave surfaces, in which connection, reference is made to the pot-shaped magnetron arrangement according to DE 35 06 227. This target arrangement can be implemented integrally or it can comprise several targets.
In its broadest aspect, the present invention relates to all stated sputtering techniques and appropriate magnetic field enhanced sputtering arrangements.
Regarding a planar magnetron, it is known from DE-A-33 31 245 as well as from U.S. Pat. No. 5,130,005, with respect to the realization of a relative motion between a magnetic field flux and a target surface, to move a magnet arrangement under the target arrangement. According to DE-A-33 31 245, for this purpose a magnet arrangement is moved along the target arrangement in a cooling medium chamber, which is closed off on one side from the target arrangement by holding plates. This magnet arrangement is moved eccentrically with respect to an axis of rotation or it is additionally guided by cams. In this way a tunnel-shaped magnetic field is generated, moving along the target surface to be sputtered. The rotational drive of the magnet arrangement takes place either through the flow of the cooling medium, namely water, through the cooling chamber, or via a drive shaft extending through the chamber wall.
A magnetic field enhanced sputtering arrangement of the above mentioned type and implemented as a planar magnetron, is known from U.S. Pat. No. 5,130,005. It comprises a housing, on the front face of which a target arrangement can be mounted, which here comprises exclusively the target and the target plate below it. This target arrangement can only be mounted or dismounted by dismantling the arrangement. The housing defines an annular chamber adjoining the mounting plate. A magnet carrier is movably supported about a hinge pin in the housing. The magnet in a magnet arrangement including the carrier, generates a magnetic field whose flux penetrates through the region of the target. The magnetic field is shifted by the relative rotational movement between the magnet carrier arrangement and the target, which is stationary in the housing.
Furthermore, an electric motor is provided which acts upon the magnet carrier arrangement via toothed belts and gearing via a pinion axle which extends through the wall of the chamber. In this arrangement, it is a disadvantage that the electric motor and the drive transmission provided between the magnet carrier and the electric motor, take up a great deal of space. Additionally, the drive motor is mounted at an offset position from the annular chamber which function as a cooling chamber. The drive motor thus must be cooled separately. A further disadvantage is that by means of an expensive electronic monitoring system, the movement of the magnet arrangement itself must be monitored in order to detect defects between the drive motor and the magnet arrangement.